In this episode, we’ll combat the stuttery mess of wrongly imported or ingested interlaced video footage by swapping the field order with the help of the Matte Key real-time effect. Buckle up, this one’s going to get geeky! And don’t forget to check out the show notes for more.

1080i – upper field firstNTSC – lower field firstPAL (except PAL DV) – upper field firstDV (PAL/NTSC) – lower field firstPAL (Avid DV Codec) – upper field first (Simply because it’s more fun. No, actually because they wanted to stay with the broadcast field order.)

Confused yet? Pop quiz in five minutes!

18 Comments

udosauer

Hello Chistian,

your solution will add a shift to the whole video of one field. [2 1] [4 3] gets [2 3] [4 *] the first and the last field will be lost, and edits will not be one the edge of a frame!To swap the field order if would be necessary to shift the frame one line up (but i think you cant move pixelwise with avid). If you want to change the field dominace you also have to move one field up or down to avoid spatial misalignment. On a pc i normaly use a simple avisynth script to convert a clip and then import it to avid (see: http://avisynth.org/mediawiki/Interlaced_fieldb…)

regardsUdo

avidscreencast

Hi Udo,

you are of course absolutely correct. However, I do think the method shown in the screencast has more benefits than disadvantages. Would you agree?

While I do recognize that not editing on the edge of a frame can be bad (e.g. with precut footage), I wouldn't think it poses a great problem with raw material?

so I tried to test this by importing some NTSC D1 720×486 footage…but even when I forced the field order to “upper”…my footage looked fine! Is there an auto-correct feature in Avid that is fixing my field order for me, perhaps?

Also, I assume to make your 720×480 template work with 720×486 footage, I'd need to check “crop/pad for DV scan line” when importing the scanline graphic?

avidscreencast

In case the video is encoded with an Avid Codec, the Import Settings concerning field order will be ignored (because they know better). So maybe that's why you can't see the difference.

In my example, I exported a small portion of the video as Quicktime with the Animation codec and then imported it with the wrong field order. Worked like a charm ;)

As for the NTSC D1 resolution, I just added a new scanline image that is 720×486, because I guess otherwise the lowest 6 lines wouldn't be affected by the field order change (I'm in PAL land, though, and do not have a lot of experience with the weird resolution difference of D1 and DV).